1. Field of the Invention
The present invention relates to a wheeled vehicle provided with an oscillating axle, and in particular to an earth-moving vehicle.
2. Description of the Background of the Invention
Earth-moving vehicles on wheels in general comprise a bottom chassis and a top chassis, which is coupled to the bottom chassis by means of a thrust bearing for rotating about a vertical axis and is equipped with a driving cab and with an operating arm. The bottom chassis is coupled to the front wheels by means of a front axle, which is in general able to oscillate with respect to the bottom chassis about a longitudinal axis of the vehicle.
Oscillation of the front axle enables the vehicle to adapt to the irregularities of the terrain during its displacements, and can be disabled by means of a manual command issued by the driver, which blocks two hydraulic cylinders that are carried by the bottom chassis and are provided with respective rods, each of which is coupled to a corresponding axle shaft. In particular, oscillation of the axle must necessarily be disabled when the vehicle carries out operations of digging and when the rotation of the top chassis and thus of the operating arm about the vertical axis, with respect to the longitudinal axis of the vehicle, becomes greater than a comfort angle, beyond which the tilt of the vehicle becomes too great for comfortable operation.
The known solutions just described require the operator to switch the control for blocking and releasing the cylinders on the basis of his own experience, his own sensitivity, and his own promptness in identifying the rotation of the chassis.
In addition, during digging operations the driver not only has to switch blocking and release of the axle manually, but must also brake the wheels using a corresponding brake pedal, so that it is far from convenient to activate and deactivate two controls repeatedly, i.e., the one for blocking the cylinders and the one for braking, when the vehicle has to carry out various operations of digging and of displacement alternately with respect to one another, as commonly occurs on worksites where digging operations are carried out.
The purpose of the present invention is to provide a wheeled vehicle equipped with an oscillating axle, which will enable the problems outlined above to be solved in a simple and economically advantageous way.